Abstract
Human Immunodeficiency Virus-1 (HIV) remains a global health challenge due to the latent HIV reservoirs in people living with HIV (PLWH). Dormant yet replication competent HIV harbored in the resting CD4+ T cells cannot be purged by antiretroviral therapy (ART) alone. One approach of HIV cure is the “Kick and Kill” strategy where latency reversal agents (LRAs) have been implemented to disrupt latent HIV, expecting to eradicate HIV reservoirs by viral cytopathic effect or immune-mediated clearance. Protein Kinase C agonists (PKCa), a family of LRAs, have demonstrated the ability to disrupt latent HIV to an extent. However, the toxicity of PKCa remains a concern in vivo. Early growth response protein 1 (EGR1) is a downstream target of PKCa during latency reversal. Here, we show that PKCa induces EGR1 which directly drives Tat-dependent HIV transcription. Resveratrol, a natural phytoalexin found in grapes and various plants, induces Egr1 expression and disrupts latent HIV in several HIV latency models in vitro and in CD4+ T cells isolated from ART-suppressed PLWH ex vivo. In the primary CD4+ T cells, resveratrol does not induce immune activation at the dosage that it reverses latency, indicating that targeting EGR1 may be able to reverse latency and bypass PKCa-induced immune activation.
Highlights
Integration of human immunodeficiency virus-1 (HIV) provirus in the human genome allows HIV to persist in resting CD4+ T cells in people living with HIV (PLWH), known as latent HIV reservoirs
J-Lat A1, Jurkat cell model of HIV latency, was treated with several Protein Kinase C agonists (PKCa) (phorbol 12-myristate 13-acetate (PMA), prostratin, bryostatin-1 and PEP005) at optimized concentrations (Darcis et al, 2015; Jiang et al, 2015) to determine if there was any enhancement of Early growth response protein 1 (EGR1) expression in HIV reactivated cells (Figure 1)
We examined the expression of Target of EGR1 (TOE1), which has been characterized as a direct downstream target of EGR1 and functions as an inhibitor of HIV replication (Sperandio et al, 2015)
Summary
Integration of human immunodeficiency virus-1 (HIV) provirus in the human genome allows HIV to persist in resting CD4+ T cells in people living with HIV (PLWH), known as latent HIV reservoirs. Prolonged use of antiretroviral therapy (ART) mitigates progression of HIV infection; it is not a cure as it fails to eradicate latent HIV infected immune cells. Latency Reversal via EGR Induction that long-term ART would need to be sustained for a minimum of 60 years due to the inability to purge the reservoirs (Finzi et al, 1999; Crooks et al, 2015; Siliciano and Siliciano, 2015). The consequence of discontinuing ART leads to rapid viral rebound, usually within weeks. Current ART has no impact on the quiescent viral reservoirs due to the extremely low levels of HIV expressed in the immune cells. An approach to directly target latent HIV reservoirs is urgently needed
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